Software Process Models 原型模型的特点 原型作为标识软件需求的一种机制，原 型被建造仅是为了定义需求，之后就该 被抛弃（或至少部分抛弃）； 实际的软件在充分考虑了质量和可维护 性之后才被开发 ● ● ●
Software Process Models 原型模型的特点： • 原型作为标识软件需求的一种机制，原 型被建造仅是为了定义需求，之后就该 被抛弃（或至少部分抛弃）； • 实际的软件在充分考虑了质量和可维护 性之后才被开发
● Software Process Models Evolutionary software process models (演化软件过程模型 。 There is growing recognition that software,like all complex systems,evolves over a period of time.Business and product requirements often change as development proceeds,making a straight path to an end product unrealistic. 人们已经越来越认识到软件就象所有复杂系统一样要经过一段时 间的演化。业务和产品需求随着开发的发展常常发生改变，想找 到最终产品的一条直线路径是不可能的
Software Process Models Evolutionary software process models (演化软件过程模型) • There is growing recognition that software, like all complex systems, evolves over a period of time. Business and product requirements often change as development proceeds, making a straight path to an end product unrealistic. 人们已经越来越认识到软件就象所有复杂系统一样要经过一段时 间的演化。业务和产品需求随着开发的发展常常发生改变，想找 到最终产品的一条直线路径是不可能的
● ● Software Process Models Evolutionary software process models (演化软件过程模型 Tight market deadlines make completion of a comprehensive software product impossible,but a limited version must be introduced to meet competitive or business pressure;a set of core product or system requirements is well understood,but the details of product or system extensions have yet to be defined 紧迫的市场期限使得难以完成一个完善的软件产品，但可以先提 交一个有限的版本以对付竞争或商业的压力：只要核心产品或系 统需求能够很好地理解，而产品或系统的细节部分可以进一步定 义
Software Process Models Evolutionary software process models (演化软件过程模型) • Tight market deadlines make completion of a comprehensive software product impossible, but a limited version must be introduced to meet competitive or business pressure; a set of core product or system requirements is well understood, but the details of product or system extensions have yet to be defined. 紧迫的市场期限使得难以完成一个完善的软件产品，但可以先提 交一个有限的版本以对付竞争或商业的压力；只要核心产品或系 统需求能够很好地理解，而产品或系统的细节部分可以进一步定 义
● ● Software Process Models Evolutionary software process models (演化软件过程模型 。 Evolutionary models are iterative.They are characterized in a manner that enables software engineers to develop increasingly more complete versions of the software. 演化模型是利用一种迭代的思想方法，它的特征是使 软件工程师渐进地开发逐步完善的软件版本。 The incremental model(增量模型) The spiral model(螺旋模型)
Software Process Models Evolutionary software process models (演化软件过程模型) • Evolutionary models are iterative. They are characterized in a manner that enables software engineers to develop increasingly more complete versions of the software. 演化模型是利用一种迭代的思想方法，它的特征是使 软件工程师渐进地开发逐步完善的软件版本。 • The incremental model (增量模型) • The spiral model (螺旋模型)
Software Process Models The incremental model(增量模型 分析 设计 编码 测试 增量1 分析 设计 编码 测试 增量2 分析 设计 编码 测试 增量3
Software Process Models The incremental model (增量模型) 分析 设计 编码 测试 分析 设计 编码 测试 分析 设计 编码 测试 增量1 增量2 增量3